The crucial turning point in Habermas' career came in the early 1970s, when he broke finally and unmistakably with key elements of the Hegelian and Marxian legacy; it was in this context that he wrestled with the utopias of the student movement. Habermas thus cut the cord connecting him to this tradition, which he previously seemed to be continuing with mere critical modifications. As a consequence of this break, he was to introduce a number of new theoretical elements into his thought, enabling him to advance towards his own theoretical synthesis.
First, Habermas abandons the idea that history can be understood as a process of the formation of the human species as a whole. In the work of Marx, humanity had been conceived in Hegelian fashion as, so to speak, a macrosubject. Following lengthy periods of alienation, this subject would regain consciousness in the post-capitalist era. This single subject of humanity as a whole – Habermas emphatically states – does not exist; the notion that later generations as a whole are always able to stand on the shoulders of those who came before and that we can thus expect humanity as such to develop further in seamless fashion is an utterly unjustified idealization. It is simply not the case that the knowledge held by the forebears is simply transferred to all their descendants, that the future generations need only to build on that which the forefathers knew and what they established in fixed and immutable fashion.